Animating a shape key that has been hooked to a driver
Custom properties on face bone.

Would leave the drivers as, is and animate the custom property that drives the jaw.  In this case its the "jaw_down" prop on the "face" pose bone.  Can see this from  the driver variables in your screen shot, just below your red circle.

Select the face bone in pose mode and the custom properties are shown on bone properties panel (as in image below) or as stated in your q, in the 3d view properties panel N